A large number of high melting fluorocarbon polymers possess a combination of mechanical, dielectric and chemical properties which make them particularly useful as electrical insulation materials. In order to maximize utilization of these fluorocarbon polymers under high temperature or overload conditions, crosslinking of the fluorocarbon polymers is required. Crosslinking of high temperature resistant fluorocarbon polymers is particularly difficult since the polymers are normally processed at temperatures which are too high for most chemical crosslinking agents. As an alternative to chemical crosslinking, irradiation crosslinking of these polymers has been tried. However, to achieve a suitable level of crosslinking without degradation, it is necessary to add a crosslinking agent or coreactant to the fluorocarbon polymers, a so-called "prorad".
The prior art teaches the existence of a variety of prorads. See for example U.S. Pat. Nos. 3,970,770, 3,985,716, 3,911,192, 3,894,118, 3,840,619, 3,763,222 and 3,995,091.
However, all of these prior art crosslinking agents suffer from one or more shortcomings in comparison with the crosslinking agents of the present invention.